iAbstract: Safranal, a GRAS-approved flavor compound with antioxidant and anti-inflammatory activities, is sourced almost exclusively from Crocus sativus stigmas at prohibitively high cost. Gardenia jasminoides , a medicine and food homology plant, has been proposed as an alternative, but whether its fruits naturally accumulate safranal remains controversial. Here, we quantified safranal in four fruit tissues (green pericarp, green sarcocarp, red pericarp, red sarcocarp) at two ripening stages using HS-SPME-GC-MS and LC-MS/MS, and characterized the expression of 14 core biosynthetic genes by qRT-PCR. Safranal was detected in all tissues, peaking in red sarcocarp (38.17 ng/g FW), followed by red pericarp (24.00 ng/g FW), green sarcocarp (1.40 ng/g FW), and green pericarp (0.28 ng/g FW). Although the levels are lower than those in C. sativus stigmas, the high fruit biomass and established cultivation of G. jasminoides warrant further investigation into whether its processing residues can serve as an alternative source of this GRAS flavor compound. Carotenogenic genes ( GjPSY , GjPDS , GjZDS , GjLCYB , GjBCH ) were predominantly upregulated in red pericarp, consistent with zeaxanthin accumulation. GjCCD2 was green-pericarp-specific, whereas GjCCD4a dominated in red tissues; six GjUGT709G1 paralogs showed divergent tissue- and stage-dependent expression. Together, GjCCD2 , GjCCD4a , and GjUGT709G1 paralogs represent candidates potentially contributing to safranal production in G. jasminoides fruits. These findings provide the first systematic evidence that safranal naturally accumulates in G. jasminoides fruits in a tissue-specific manner associated with transcriptional regulation. This work provides a molecular foundation for breeding and metabolic engineering strategies aimed at enhancing safranal yield in G. jasminoides .
Danshen ( Salvia miltiorrhiza Bunge) exhibits marked regional differences in secondary metabolism, but their relationships with root-associated microbiomes remain insufficiently understood. Relationships between root-associated microbiomes and regional quality traits of Danshen were examined using samples from 19 cultivated fields in five major production regions of China. Root biomass, major bioactive constituents, and bacterial and fungal communities in root-inhabiting and rhizosphere compartments were analyzed. Regional patterns were distinct. Samples from Shandong (SD) had higher root biomass and tanshinone (TS) contents, whereas those from Sichuan (SC) had higher salvianolic acid B levels. Root-inhabiting bacterial alpha diversity was lowest in SD samples, where specific taxa, including Pseudomonas and Pantoea , were enriched. Salvianolic acid variation exhibited distinct associations with fungal communities. Variance partitioning also indicated that soil properties and microbiome variation explained both shared and independent fractions of regional quality differences. Network and trait-correlation analyses identified a Pseudomonas -affiliated operational taxonomic unit closely associated with both root biomass and TS accumulation. A bioaugmentation assay examined the functional potential of a culturable Pseudomonas isolate, Pseudomonas putida strain 3–37, obtained from Danshen roots. Under the tested conditions, strain 3–37 treatment promoted plant growth and increased total TS accumulation. These findings indicate closer associations of root-inhabiting bacterial communities with root biomass and tanshinone accumulation and of fungal communities with salvianolic acid variation. Therefore, strain 3–37 may serve as a candidate microbial resource for Danshen cultivation.
The metabolites and regulatory mechanisms associated with contrasting stem coloration in Polygonatum cyrtonema remain incompletely understood. We compared red- and green-stem landraces at three matched developmental stages to distinguish persistent pigmentation-associated differences from stage-specific variation. Targeted LC–MS/MS profiling identified 27, 25, and 23 differentially accumulated metabolites, respectively, including 16 anthocyanins shared across stages. Five shared anthocyanins were supported by corresponding authentic-standard measurements, whereas 11 were putatively annotated through database matching and their reported amounts were treated as semi-quantitative estimates. Four red-stem-enriched signals were putatively assigned to coumaroylated petunidin or malvidin glycosides. Transcriptomic analysis prioritized the candidate acyltransferase gene PcAAT1 , whose transient expression in Nicotiana benthamiana increased total anthocyanins approximately sixfold. Silencing PcAAT1 in P. cyrtonema reduced purple stem coloration and total anthocyanin content. PcNAC68 activated the PcAAT1 promoter and recognized a CATGTG-containing region in yeast and in vitro. Silencing PcNAC68 in native plants reduced PcAAT1 transcript levels and anthocyanin content. These results support a PcNAC68 – PcAAT1 regulatory relationship contributing to pigmentation. PcAAT1 catalytic specificity remains to be established.
The development of sustainable bio-based substitutes for fossil-fuel-derived epoxy resins is vital for reducing the environmental impact of polymer coatings. In this work, a sustainable aqueous interfacial strategy was developed to produce epoxidized Eucommia ulmoides gum (EEUG) as a high-performance bio-based epoxy coating material. Unlike conventional solution-based epoxidation methods, this approach uses water as the reaction medium and enables efficient epoxidation via an in situ hydrogen peroxide/acetic acid oxidation system, thereby avoiding large quantities of organic solvents. The extent of epoxidation was governed by tuning the reaction parameters, yielding a maximum epoxy content of 0.120 mol per 100 g of resin. Structural characterization confirmed the successful conversion of CC bonds into epoxy groups while preserving the trans-polyisoprene backbone of Eucommia ulmoides gum. The resulting EEUG-based coating exhibited thermal stability and chemical resistance comparable to those of conventional E51 epoxy coatings, along with enhanced flexibility, damping capability, and hydrothermal adhesion retention. Electrochemical impedance spectroscopy (EIS) and neutral salt spray (NSS) tests demonstrated excellent anti-corrosion performance, with the impedance modulus of coating (|Z| 0.01 Hz ) maintaining approximately 10⁸ Ω·cm² after 30 days of immersion in a simulated seawater solution. This work demonstrates a green and scalable pathway for converting renewable biomass into functional epoxy materials for sustainable protective coatings.
Hevea brasiliensis is the sole commercial source of natural rubber at industrial scale, yet the polygenic architecture underlying latex productivity has constrained the pace of genetic improvement. In this study, we constructed an ultra-dense SNP-based linkage map from whole-genome resequencing data generated for a biparental F1 population (IAN-873 ×CATAS-106) and employed to map quantitative trait loci (QTLs) for latex yield related traits across two environments. A total of 20,730,159 high-confidence SNPs were condensed into 5069 recombination bin markers spanning 18 linkage groups and genetic length of 10,779.69 cM, with a mean inter-bin interval of 2.35 cM. QTL analysis identified 146 loci associated with the three latex yield related traits, of which 22 were classified as stable and/or colocalized across environments, with favorable additive alleles predominantly contributed by the elite parent (IAN-873). Candidate gene mining within six prioritized stable QTL clusters yielded nine functionally annotated genes with predicted roles in isoprenoid precursor supply and transcriptional regulation of laticifer metabolism. Parallel transcriptome profiling of latex from phenotypically contrasting individuals identified 1573 differentially expressed genes, from which a manually curated subset of 75 genes with established functional annotation to rubber biosynthesis, encompassing mevalonate pathway enzymes, rubber particle proteins, and multiple transcription factor families, was selected for candidate gene prioritization. Notably, four out of nine genes (HbHMGR1, HbFPS1, HbACAT2, and HbERF-RAP2–12) were independently supported by both positional QTL evidence and differential expression data, establishing them as high-priority candidates for functional validation. These findings advance the molecular understanding of latex biosynthesis and deliver valuable genomic resources, including a high-resolution linkage map, stable QTL intervals, and integrated candidate genes, for implementation in marker-assisted and genomic selection programs targeting rubber yield improvement in rubber tree.
